The present invention relates to polymerization inhibitors and their removal from monomers.
Since monomers are by nature reactive, it is conventional practice to add a polymerization inhibitor to prevent unwanted, premature polymerization while the monomer is being stored or transported. Hydroquinone and hydroquinone-monomethyl ether are two inhibitors used for this purpose. While the inhibitors thus perform a valuable function, their very usefulness requires that they be removed from the monomer when the user wishes to polymerize the monomer. Conventional techniques for removing the inhibitor (distillation, crystallization, washing, solid adsorbtion) can be destructive to the monomer, or inefficient, and generally must be tailor-made based on the exact composition of the inhibitor, the monomer, and the solvent in which the monomer is dissolved. It is desirable to be able to remove inhibitors quickly in high yield, using inexpensive materials and minimizing the use of even those materials. To this end, the present inventors have discovered new and effective inhibitors which can be removed simply and efficiently from monomer-solvent systems.